Office of Engineering & Technology Seeks Additional Information Regarding Client-to-Client Device Communications in the 6 GHz Band, 6644-6645 [2021-01404]

Agencies

• FEDERAL COMMUNICATIONS COMMISSION

[Federal Register Volume 86, Number 13 (Friday, January 22, 2021)]
[Notices]
[Pages 6644-6645]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-01404]


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FEDERAL COMMUNICATIONS COMMISSION

[ET Docket No. 18-295; GN Docket No. 17-183; DA 21-7; FRS 17404]


Office of Engineering & Technology Seeks Additional Information 
Regarding Client-to-Client Device Communications in the 6 GHz Band

AGENCY: Federal Communications Commission.

ACTION: Notice.

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SUMMARY: In this document, the Office of Engineering and Technology 
seeks additional information to supplement the record on whether the 
Commission should permit direct communications between unlicensed 6 GHz 
band client devices.

DATES: Comments are due on or before February 22, 2021, and reply 
comments are due on or before March 23, 2021.

ADDRESSES: Federal Communications Commission, 45 L Street NE, 
Washington, DC 20554.

FOR FURTHER INFORMATION CONTACT: Nicholas Oros, Office of Engineering 
and Technology, 202-418-0636, [email protected].

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's 
document, Public Notice, DA 21-7, ET Docket No. 18-295, GN Docket No. 
17-183, released January 11, 2021. The full text of this document is 
available for public inspection and can be downloaded at: https://www.fcc.gov/document/oet-seeks-info-6-ghz-u-nii-client-client-device-communications or by using the search function for ET Docket No. 18-295 
on the Commission's ECFS web page at www.fcc.gov/ecfs.

Synopsis

    1. In the 6 GHz Further Notice, the Commission sought comment on 
additional actions that it should take to further expand unlicensed 
operations in the 6 GHz band through revisions to the existing rules 
for standard-power or low-power indoor operations or by authorizing a 
third type of operation, very low power operations. Among the comments 
filed, unlicensed proponents requested that the Commission modify its 
low-power indoor device rules to permit client-to-client device 
communications, which they assert would enable additional types of 
innovative unlicensed operations in the band. The Fixed Wireless 
Communications Coalition opposes any such revisions and asserts that 
there is no record support for permitting client-to-client 
communications in this band.
    2. In the 6 GHz Order, the Commission prohibited unlicensed client 
devices from acting as ``mobile hotspots'' because ``[p]ermitting a 
client device operating under the control of an access point to 
authorize the operation of additional client devices could potentially 
increase the distance between these additional client devices and the 
access point and increase the potential for harmful interference to 
fixed service receivers or electronic news gathering operations.'' To 
avoid this situation, the Commission's rules prohibit 6 GHz U-NII 
client devices from directly communicating with one another. The 
Commission did not, however, examine whether a more limited approach to 
indoor client-to-client communications within the ambit of the 6 GHz 
Notice should be permissible--e.g., when a client is not acting as a 
mobile hotspot. Accordingly, Apple, Broadcom et al. suggest that client 
devices be permitted to directly communicate with each other if they 
can decode an enabling signal transmitted by a low-power indoor access 
point within the last four seconds. They suggest that the Commission 
could further constrain client-to-client communications by requiring 
that the enabling signal be received at a signal strength of at least -
99 dBm/MHz. According to Apple, Broadcom et al., as a client device 
could communicate at this signal level with a low-power indoor access 
point in a traditional access-point-to-client topology under the 
existing rules, this would ensure each individual client participating 
in client-to-client communications is safely inside the area where a 
client device is authorized to communicate with an access point
    3. The Commission takes this opportunity to invite interested 
parties to supplement the record, for the Commission's consideration, 
on whether and under what circumstances client devices could be 
permitted to directly communicate with each other in a limited manner 
consistent with the rationale underlying the Commission's decisions in 
the 6 GHz Order that were targeted at protecting incumbent licensed 
services. More specifically, the Commission invites comment on whether 
to permit 6 GHz U-NII client devices to directly communicate when they 
are under the control of or have received an enabling signal from a 
low-power indoor access point. As an initial matter, commenters should 
explain how they define an enabling signal, what characteristics it 
must have, how it is similar or different from signals, such as 
beacons, that access points already use to connect with client devices, 
and the degree to which an enabling signal would tether a client device 
not under the direct control of an access point to that access point. 
Commenters should also provide information on the types of applications 
that direct client-to-client communications would enable that cannot be 
accomplished by communications through an access point. In addition, 
commenters advocating for rule changes should address whether direct 
client-to-client communications should be under the current power 
limits or restricted to lower power limits to reduce the potential for 
harmful interference to incumbent operations. In this connection, the 
Commission notes that client devices under the control of a low-power 
indoor access point are permitted to operate up to 24 dBm EIRP over 
320-megahertz channels (or -1 dBm/MHz).
    4. As the 6 GHz Order explained, the requirement that 6 GHz U-NII 
client devices operate under the control of either a standard-power or 
low-power indoor access point is designed to prevent client devices 
from causing harmful interference by limiting their operation either to 
outdoors in areas where the AFC system has determined that interference 
will not occur or to indoor locations where other factors such as 
building entry loss prevent harmful interference. In particular, 
operations under the control of a low-power indoor access point is 
aimed at restricting operation of the client devices to indoor 
locations. It may be possible for a client device to receive an 
enabling signal from an access point even when the enabling signal is 
too weak to enable the client device to conduct communications with the 
access point. In such situations, the weak received signal level makes 
it more likely that the client device could be outdoors. By requiring 
the enabling signal have a specific signal strength, this problem could 
be potentially avoided. If the Commission were to adopt rules 
permitting client-to-client communications, should it require the 
enabling signal from the low-power

[[Page 6645]]

indoor access point to be received by the client device with a 
particular signal level? Apple, Broadcom et al. suggested -99 dBm/MHz: 
Is this level appropriate? If not, what signal level would be 
appropriate for this purpose? How can a specific signal level be 
correlated with the current requirement that the client device be under 
the control of an access point? For example, under such an approach, 
should the enabling signal level be of such a strength to effectively 
require that the signal levels between the access point and client 
device be sufficiently strong to permit bi-directional communications 
between the client devices and the access point, thereby ensuring that 
both client devices are sufficiently close to the access point? How 
frequently should a client device be required to receive an enabling 
signal to continue transmitting to another client device?
    5. If permitted, should the client devices be limited to receiving 
an enabling signal from the same access point or could client-to-client 
communications be permitted so long as each client device receives an 
enabling signal from any authorized access point? Apple, Broadcom et 
al.'s suggestion would potentially permit two client devices to 
communicate even if they receive enabling signals from two different 
access points. For example, client devices in two different buildings 
receiving enabling signals from different low-power indoor access 
points could attempt to communicate with each other. Would permitting 
this to occur increase the potential for the client devices to cause 
harmful interference to licensed services? How would a requirement for 
both devices to receive an enabling signal from the same access point 
be implemented? Or should other configurations be permitted? For 
example, could a client device controlled by a standard power access 
point be permitted to communicate with a client device controlled by a 
low-power indoor access point? Could client-to-client communications be 
permitted between devices when both clients are controlled by a 
standard power access point? If so, are any changes needed to the AFC 
systems? Must the enabling signal be received on the same channel for 
each device under any of the scenarios contemplated? Under any 
envisioned client-to-client communication scenario, commenters should 
provide detailed descriptions of how such communications can be enabled 
including how such communications fit under the current rules that 
limit client devices to operating only under the control of a standard 
power access point or a low-power indoor access point or whether, and 
which, rules would need to be modified. Commenters should provide 
detailed analysis of how any client-to-client communication 
configurations they prefer would protect incumbent operations from 
harmful interference. Finally, commenters should provide any other 
information they believe relevant to evaluating whether direct client-
to-client communications consistent with the rationale of the 
Commission in the 6 GHz Order should be permitted, including any 
alternative methods or necessary rule changes not directly noted above.

Federal Communications Commission.
Ronald T. Repasi,
Acting Chief, Office of Engineering and Technology.
[FR Doc. 2021-01404 Filed 1-21-21; 8:45 am]
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